Control apparatus



w. H. WANNAMAKER, JR 2,685,645

CONTROL APPARATUS Original Filed June 22, 1944 I2 II 1| I3 0 A0 F 2| a; 9' v6 G Mum INVENTOR.

WILLIAM H WANNAMAKER JR Patented Aug. 3, 1954 UNITE-D3- STATES: PATENT! OFFICE CONTROL APPARATUS:-

William H. Wannamaker; J r., Flour-town; Pa.,' as-- signer to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn.,"a corporation.of.-.'

Delaware Original application June 22,. 1944, Serial No;

541,576, new PatentNo. 2,514 918, dated July 194-9; Serial No. 92,480'

7 Claims; (Cl. 250-457) ply to-the. burner when the character of the flame: is abnormal- This application-is a division of my prior application Serial No-.541,576. filed June 22-, 1944, on which Patent No. 2,514,918-was granted July 11,1950, and Which-"discloses and claims novel subject matter disclosed but not claimed herein.-

The subject matterxof this application is also disclosed: in :my; copending application bearing Serial 'No. 422,041, which was filed on April.

Thevariousfeaturesof novelty which characterize my invention-are pointed out with particularity' in the claims 1 annexed to and forminga part ofthis specification.- For a better understanding ofthe invention;--however, its advantages, and specific objectspattained with its use,- reference should be hadtor-the-accompanying drawing;and-descriptive matterin which I have illustrated. and deseribed'a preferred embodiment mechanism- C ,to closethe fuel :supply valve D for the burner;A,ywhen theburner-fiame' is extinguished orbecomeszjabnormalx The'operation oftherelavmechanism C is controlled through a circuit network'E, which has one-terminal connected to the -:burnerbody; and has" a second terminal COIlllSOtfidxtUfill electrode b extending into the flame. Saidnetworkinciudestwo valves rentsupply conductors I and-,2.

The tube .G may be of .the commercially avail-i;

. .0 and-g" enclosed in-a tube G, and. is energized" by a'transformerF having the terminals ofits primary. winding-connected .to alternatingcur- Divided and this 'applicationMay- 10;

2 I. able typeand form; known asa rectifier-beam power amplifier--tube-ll7N7-GT. The tetrode valve g in :the tube G.comprises-a cathode 3 and associated beam platesnSara "control grid '4, a screen 5, an anode 'or .plate'fi, anda filament l for heatingboth ,the cathode 3 of the valve .0 and the cathode '8 ofthe valve g,'the latter being: a diode;-- The-- diode cathode 8 and the tetrode anodefi are eachzconnected. to an energizing conductor- H Thelatter is connected.

to. one" terminal of: the secondary-winding f of the=transformer,-F. The other terminal of the winding J iscon'nectedthrougha conductor H, a condenserzqli, and a relay coil: or. winding i3 to the diode anode 9 of the diode valve 0 andto the cathode. .3 of the tetrode valve 9. 1

As shown in the ldrawi-ngsthe diode plate El and the. cathode 3 ofr -the multi-grid valve 9' int-he tube G,.Which are connected to one terminalof the cont-rolrwinding 53, are also connectedthrough a resistance l i'andra conductor l5 to the body-of the burner :A and'to a ground connectionmlfip. Ihegroundednburner body is connected through the conductor; l5 and a resist ance llto the control-:grid 4 of thevalve g.

A condenser 13 is connected inn-shunt to the resistance ME The control winding'l'a, and a conductor 19 in series therewith, connect the plate 9 and cathode 3 to the electrode b. The latter extends intothe-space which-is occupied bythe tip portion of the flame B whentheconditionof the latter is normal.

The screen grid5 ofthevalve y is connected to theconductor it! through a suitable screen grid resistor. The .filament l of the tube G is adapted to be-connectedtoa suitable source of filament, energizing current, notshown.

As is known to: those. skilled in theart, with the electrodelb extending intothe tip of the flame.B,-..as it does in the normal condition of the .fiame, the latterprovides a path for current flow. betweentheterminals formed by the electrcdelb and the body of the burner Awhich is more. hi hly. conductive, for. current flow in the direction opposite to thatsof flame propagation, i. e. .in the. direction from theelectrode b to the burner A,..than .for. current flow in the opposite direction... This. rectifying action is e7- plained. by then-fact. that. the combustion reaction maintainingthe flame isattended by, or results in,.ionization, andin. a concentration of positive ion adiacentato the burner body and a concentration of, negative ions or -electrons at the tip portion of the flame.

The charging current flowfrom thediode plate:

element 9, during each of alternate half cycles, acts through the rectifier formed by the flame B, electrode 13, and body of the burner A to maintain a potential on the control grid 3 which is more positive than that of the cathode 3 during each subsequent half cycle, in which the plate 5 of the grid valve 9 is positive. The grid valve then discharges the condenser i2 through the relay winding !3 and thereby effectively energizes the latter. The relay winding is is effectively deenergized by the extinction of the flame, and also by the development of an abnormal condition which has the efiect of connecting the electrode 1) to ground directly or through an ohmic impedance substantially smaller than the impedance due to the flame when the latter is in normal condition. In either case, the potential of the control grid 6 is then more negative than it is when said grid is electrically connected to the condenser l2 through the flame. lhe current flow through the relay winding E3 is thus greater when the flame is in its normal condition, than when it is in an abnormal condition or is extinguished.

As diagrammatically shown in the drawing, the winding 53 is the energizing winding of an A. C. relay having an armature so. When the relay winding i3 is deenergized, as a result of flame extinction or abnormality, the armature 2 connects a conductor 2! to the conductor H, and thereby completes a circuit including the conductor 2i, the actuator d of the valve D, the conductor 5 t, and the transformer secondary f. The completion of that circuit automatically closes the burner valve D.

While, in accordance with the provisions of the statutes, I have illustrated and described the best form of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in the form of the apparatus disclosed without departing from the spirit of my invention as set forth in the appended claims, and that in some cases certain features of my invention may be used to advantage without a corresponding use of other features.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In combination, a pair of terminals adapted for connection to a source of alternating cur rent, a control device, a condenser, two electrcnic valves connected in parallel with one another and in series with said control device and said condenser between said terminals, one of said valves being a diode and having an anode and a cathode, the second of said valves having a control grid, having an anode connected to the cathode of said diode valve, and having a cathode connected to the anode of said diode valve for current flow through one of said valves during half cycles of the alternating current which alternate with those during which current flows through the other valve, and means for impressing a control voltage on said grid, comprising an electrode connected to said grid, and a second electrode connected to said condenser and adapted to be conductively connected to the first mentioned electrode by a flame of predetermined length with said second electrode extending to the tip portion of the flame.

2. A combination as specified in claim 1, in which the first mentioned electrode is connected to said grid through a resistance, and is connected to the cathode of said second valve through a second resistance and a condenser in shunt to said second resistance.

3. In combination, a pair of terminals adapted for connection to a source of alternating current, a control device, a condenser having two terminals one of which is connected to one of said pair of terminals, two electronic valves connected in parallel with one another and in series with said control device and said condenser and between the second terminal of the latter and the second terminal of said pair, one of said valves being a diode and having an anode and a cathode, the second of said valves having a control grid, having an anode connected to the cathode of said diode valve, and having a cathode connected to the anode of said diode valve for current flow through one of the valves during half cycles of the alternating current which alternate with those during which current flows through the other valve, and means for impressing a control voltage on said grid, comprising an electrode connected to said grid, and a second electrode separate from said first mentioned electrode and connected to said second terminal of said condenser and adapted to be connected to said first mentioned electrode by a flame.

l. Apparatus operative to produce a predetermined efiect only upon the existence of a given condition, comprising a pair of terminals adapted for connection to a source of alternating current, a control device, a condenser, a current rectifying device connected in series with said condenser and said control device between said terminals and tending to pass current in one direction through said control device and said condenser to charge the latter during alternate half cycles of the alternating voltage of said source, said control device being operable to produce said predetermined effect only in response to continued substantial current flow through said condenser, controllable means con nected in shunt with said current rectifying device and operative when in one condition to cause a substantial current to flow through said control device and said condenser, during he intervening alternate half cycles of said voltage, in the direction opposite to said one direction, thereby to tend to discharge said condenser during the last mentioned half cycles and hence to cause continued substantial current flow through said condenser, said controllable means being operative when in a second condition to prevent said current flow in said opposite direction, a control portion included in said controllable means and operative to cause the latter to assume said one or said second condition in accordance with the character of a signal applied to said control portion, an electrical path effectively connected between said terminals and exhibiting a rectifying characteristic when said path is subjected to said given condition, whereby a unidirectional current is caused to flow over said path when the latter exhibits said rectifying characteristic, an alternating current is caused to flow over said path when the latter is effectively short-circuited, and no current is caused to flow over said path when the latter is interrupted, impedance means included in circuit with said path to develop a control signal of a character depending upon the direction of the current flow over said path, and conductors connecting said impedance means to said control portion to apply said control signal thereto to cause said controllable to assume said one condition when and only when said path exhibits said rectifying characteristic, and to cause said controllable means to assume said second con dition when said alternating current or no current lows over said path.

5. Apparatus as specified in claim 4, wherein said path includes first and second electrode means having at least a portion of a flame therebetween when said path is subjected to said given condition.

6. Apparatus as specified in claim 4, wherein said controllable means is a controllable rectifier which is reversely connected across said current rectifying device.

7. Apparatus as specified in claim 6, wherein said current rectifying device has a cathode directly connected to one of said terminals and has an anode connected to the other of said terminals through said control device and said condenser in series in the order stated, wherein said controllable rectifier is an electronic valve having an anode connected to the cathode of said current rectifying device, having a cathode connected to the anode of said current rectifying device, and having a control electrode included with the last mentioned cathode in said control portion, wherein said impedance means comprises a resistor and a condenser connected in parallel with on another between the cathode control electrode of said valve, and wherein said path is connected between the end of said pedance means connected to said control electrode and the junction between said control device and said condenser.

Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,084,186 Braden June 15, 1937 2,175,017 Cockrell Oct. 3, 1939 2,263,430 Wannamaker Nov. 18, 1941 2,313,943 Jones Mar. 16, 1943 2,352,143 Wills June 20, 1944 2,422,574 MacLaren et a1. June 17, 1947 2,528,589 Frick Nov. '7, 1950 

